You need to describe more what you want to do.

Show us an example in code how you have done it now

Where I can place below reference ?

<script src="https://maps.googleapis.com/maps/api/js?key=Your_Key&libraries=places" async defer></script>

Currently I placed this in View directly.

Is there any way to include in web.config and access from the same?

In the view for the page you need it seems like a good ideá or in the layout if you are using it in many places.

Also put your key in web.config so you not hard code it in the view